DIRECT HEATING CATHODE CONSTRUCTION AND ITS MANUFACTURING METHOD

摘要

PURPOSE:To devise power savings by forming filaments as coil shapes and making heater voltages higher and heater currents less. CONSTITUTION:Electron emitting materials 3 are coated at an approximate center portion of a coil filament and which is installed to a filament attaching material 2. The attaching material 2 is made engaged with a leading material 4 and the leading material 4 is supported by an insulating base plate 5. This coil filament is spanned perpendicularly against to a central axis of an electron beam passing hole of the first grid electrode and an approximate center of electron emitting material is made coincide with a central axis of an electron beam passing hole. In this manner, the coil filament can be maintained at a state keeping a stress by a spring back quantity of a coil and as a result to contain long fine wire, a direct heating cathode construction of high heater voltage and less heater current is obtained.